Servomotor control valve



Oct. 6, 1953 E. R. PRICE SERVOMOTOR CONTROL VALVE 2 Sheets-Sheet 1Original Filed March 22, 1943 mwzuron. 54/54 A. F a/c5 Oct. 6, 1953 E.R. PRICE 2,654,391

SERVOMOTOR CONTROL VALVE Original Filed March 22, 1943 2 Sheets-Sheet 2M0 a v4 Z757 I 1N VEN TOR.

Arrow/5v Patented Qcto 6, 1953 SERVOMOTOR CONTROL VALVE Earl R. Price,South Bend, Ind., assignor to Bendix Aviation Corporation, South Bend,11111., a corporation of Delaware Original application March 22, 1943,Serial No.

479,974, now Patent No. 2,446,884, dated August 10, 1948.

Divided and this application May 29, 1947, Serial No. 751,283

8 Claims.

This invention relates to a servo-motor control valve, particularlyintended to operate a differential air pressure power cylinder. Thepresent application is a division of Price application Serial No.479,974, filed March 22, 1943, now Patent No. 2,446,884, issued August10, 1948.

In general, it is the object of the present invention to provide asimplified and more eflicient control valve, which will constitute animprovement over the control valve, for example, of Johnson Patent No.2,111,322.

The present control valve is considered to constitute an improvementover that disclosed in the Johnson patent in at least the followingrespects:

(a) It provides a simpler and less expensive construction by eliminatingthe floating control lever of the patented valve;

(12) It increases efficiency of the valve by utilizing a flexible shaft,or rod, to interconnect two aligned poppets, thereby permitting thepoppets to be self-aligning in lapped position;

It limits the aforementioned flexibility to the lateral direction only,avoiding flexibility, or give, in the longitudinal direction; and

(d) It obtains the foregoing advantages without necessitating largerport openings, as is the case with a single poppet arrangement, in whichthe valve element for one port constitutes the valve seat for the otherport.

Other objects and advantages of the present invention will becomeapparent during the following description, reference being had thereinto the accompanying drawings, in which:

Figure 1 is a view, partly diagrammatic and partly sectional, or a powerbraking system which utilizes my improved control valve;

Figure 2 is a closeup of the valve shown in Figure 1;

Figure 3 is a view, partly in side elevation and partly in section,showing the commercial embodiment of the power braking system of Figure1;

Figure 4 is an enlarged section taken through the control valve ofFigure 3; and

Figure 5 is an enlarged section taken through the poppet valvearrangement of Figure 4.

In order to explain fully the function of my improved control valve, acomplete power braking system has been illustrated. As shown in Figurel, the braking system includes a master cylinder it adapted to putliquid under pressure, and a plurality of conventional wheel cylinders12 adapted to actuate the brakes, which are diagrammatically illustratedat M. A manually operable pedal [6, pivoted at l8, has a rod 2Bextending into the interior of the master cylinder I8 and engaging thepiston therein (not shown), said rod and piston being arranged to putthe liquid in themaster cylinder under pressure in response to manualactuation of the pedal It. A liquid-carrying conduit 24 is connected tomaster cylinder IE3 at master cylinder outlet 26, and said conduit 24connects the master cylinder to an auxiliary master cylinder 28. Aseparate conduit 34 connects outlet port 36 of master cylinder It to acontrol or relay valve indicated generally at 38. It will be noted thata residual pressure check valve 12 is positioned inside the mastercylinder l8, and is located between outlet 26 and outlet 36, thearrangement being such that the liquid in conduit 24 is under residualpressure, whereas the liquid in conduit 34 is under reservoir pressureonly. The reasons for this arrangement are explained at length in PatentNo. 2,446,884.

Adjacent to, and associated with, the auxiliary master cylinder 28 is apneumatic or vacuum power cylinder 38. The outlet end of the auxiliarycylinder 28, i. e., the end farthest from the power cylinder 30, isconnected by a liquid-carrying conduit to and branches 42 thereof to thewheel cylinders l2.

A pneumatic or vacuum carrying line 44, extending from a source ofvacuum, as for example, the usual intake manifold, is connected tochamber 66 of power cylinder 30. Another vacuum line 45 connectsconstant vacuum chamber at with chamber 54 of control valve 38, and,through passage 55, with chamber d8 of the power cylinder. Chambers 45and 48 are at the right side of the respective tandem pistons 41' and48, which reciprocate in the power cylinder. A pipe 50 connects thecontrol chamber of control valve 38 to chambers 5i and 53 of the powercylinder, the latter chamber being interconnected with chamber 5|through the tubular connecting rod 52.

The auxiliary cylinder 28 has a piston t2 reciprocable therein betweenthe point where conduit 24 is connected to the cylinder and the forwardend of the cylinder, which is connected by conduit 40 to the brakes.When pressure is applied by pedal 16 to the fluid in master cyl inderHi, the fluid will be forced through conduit 24 and cylinder 28 to applythe brakes. As soon as a pressure sufficient to overcome the spring incontrol valve 38 has been developed, said valve will actuate the powercylinder by creating a pressure differential over the tandem pistons 41and 49, and the pistons will exert force their seats.

s3 through a rod lilo to move piston 92 in cylinder 28, at the same timecutting ofi passage I82 through piston 92 to prevent direct fluidcommunication between conduits 2d and ill.

Referring in detail to the construction of my improved control valve 38,which is shown enlarged in Figure 2, the floating poppet assemblyincludes a pair of flexibly connected poppets I32 and E34, the poppet 32being adapted to control the admission of air to control chamber E36,and poppet :34 being adapted to control the evacuation of air from saidchamber. The chamber I38 is connected by means of control line 50 withthe power cylinder, in order that the pressure prevailing in chamber [towill also prevail at the rear of each of the tandem pistonsin the powercylinder. Chamber cc of the valve isc ontinuously connected to a sourceof vacuum by conduit 45 which connects to chamber 66 of the powercylinder. Chamber we of the valve is connected directly to theatmosphere.

The poppets its and Hi l are so connected that they move as a unit inthe axial direction but they are capable of a slight relative lateralmove gnent in order that they .may both be properly aligned with theirseats, thus preventing leakage. The poppets are connected by means of .aflexible cable H55, which permits the necessary vmovement of the poppetstoalign themselves wit In order that the structure will have sufilcientstrength to operate properly, the flexible cable 555 is encased in apair of telescoping sleeves 15c and we, each of which is connected toone or" the poppets, and each of which is pinched slightlyto retain oneend of the cable. A slight radial clearance is provided between the twosleeves, in order that lateral flexing of the cable will be permitted.

As liquid under pressure is forced into chamber ass, piston Hi1 is movedupwardly, moving the yoke Hi2 and diaphragm i2 2. This movement bringsthe valve seat into contact with pop-pet 13s cutting on chamber 538 fromthe vacuum source. Further movement upward of the piston and diaphragm,acting through the connection between the two poppets, pushes poppet 32from its seat, allowing air at atmospheric pressure to enter chamber535. The air lowing through conduit 58, enters chamber 5! at the rear ofpiston ie in the power cylinder. likewise flows through the openings H8and the hollow piston rod 52 to chamber 53 at the of piston il. Sincechambers st and 38, which are in front oi the respective pistons, areconnected to the vacuum source, the air entering chambers 5! and 53simultaneously urges both pistons forward to create pressure in themaster cylinder 28. Use of the tandem pistons ll and 49 makes itpossible to build up power equivalent to that which would be developedover a single piston twice the size of either of the tandem pistons.

When the reaction pressure of diaphragm .22 3, i. e., the pressure ofthe air in chamber 135 against the vacuum in chamber Ed, has built upsurficiently, the diaphragm will move downwardly permitting the valve toreturn to lapped posi tion, in which both the vacuum and the atmosphereports are closed.

In Figure 3, a compact working embodiment of the invention is shown. Thecontrol valve 38a and the auxiliary master cylinder 230. are mounted onthe forward end of power cylinder 33a, the control valve being locatedat one side of the auxiliary master cylinder, as shown. The port Thisair K 4 292 which leads to chamber Hits of the control valve isconnected to conduit 3 and port 2% which opens into the chamber at therear of piston 522a in the auxiliary master cylinder is connected toconduit 24.

Figure 4 shows a cross-section of the control valve 38a, and Figure 5shows a closeup of the floating poppet device. As described above, thepoppets I32 and EM are flexibly connected by meansof a cable I55, whichis encased in the telescoping sleeves lbiiand 55:), a radial clearancebeing allowed between the leeves in order to permit relative lateralmovement of the poppets to align themselves with their respective seats.

In the valve .device of Figures 4 and 5, the chamber lie is directlyconnected to atmosphere, the chamber E35 is connected to the powercylinder to operate the same, and the chamber 5 3 is connected to thevacuum source. It will therefore be apparent that the operation of thisvalve corresponds to the operation of the valve shown in Figures 1 and2,.and described above.

Although certain particular embodiments of my invention have beendescribed, it will be understood by those skilled in the art that theobject of the invention'may be attained by the. use of constructionsdifferent in certain respects from those disclosed without departingfrom the underlying principles or" the invention. I therefore desire bythe following claims to include within the scope of my invention allsuch variations and modifications by which substantially the results ofmy invention may be obtained through the use of substantially the sameor equivalent means.

I claim:

1. A valve for controlling the operation of a differentialair pressurepower device comprising a casing, a diaphragm having a first valveopening and dividing the interior of said easing into two variablevolume chambers, said casing having a second valve opening whichcommunicates with one of said chambers, a first resilient memberarranged to urge said diaphragm away'lrorn said second opening, a firstvalve element 'for controlling said first opening, a second valveelement for controlling said second opening, said valve elements beingcoupled together by means of a flexible connection which holds saidelements against movement toward or away from each other, and a secondresilient member arranged to act on said second valve element to closesaid second opening, said diaphragm being movable to close said firstopening by seating it against said first valve element.

'2. A valve for controlling the operation of a differential air pressurepower device comprising a casing, a diaphragm having a first valveopening providing a valve seat and dividing the interior of said casinginto two variable volume chambers, said casing having a second valveopening which communicates with one out said chambers, a first valveelement for controlling said first opening, and a second valve elementfor controlling said second opening, said valve elements being coupledtogether by means of a flexible connection which holds saidelementsagainst movement toward oraway from each other, said diaphragm beingmovable to close said first opening by seating it against said firstvalve element.

3. In a valve having a pair of spaced substantially aligned ports, apair of spaced substantially axially aligned valve elements, and meansconnecting said valve elements for moving them axially as a unitsimultaneously but permitting slight relative lateral movement of thevalve elements to obtain proper alignment of each valve element with itsseat, said connection comprising a cable attached to each valve elementand a pair of telescoping slightly radially spaced sleeves around saidcable, each sleeve being upported by a corresponding one of said valveele ments.

4. In a valve having a pair of spaced substantially aligned ports, apair of spaced substantially axially aligned valve elements and aconnection between said elements, said connection comprising a hollowtubular element secured to one of said elements, a boss secured to theother of said elements and enterable into the bore of said tubularelement, and a non-resilient flexible member eifectively secured at itsends to said valve elements, the diameters of said bore and said bossbeing of such respective sizes as to provide for lateral relativemovement therebetween, said non-resilient flexible member preventingoppositely directed movements of said valve elements.

5. In a valve having a pair of spaced substantially aligned ports, apair of spaced substantially axially aligned poppets for controllingsaid ports, and means connecting said poppets for substantiallysimultaneous movement in an axial direction but permitting slightrelative lateral movement of the poppets to obtain proper alignment ofeach poppet with its seat, said connection comprising a cable attachedto each poppet and a pair of telescoping slightly radially spacedsleeves around said cable, each sleeve being supported by acorresponding one of said poppets.

6. In a valve having a pair of spaced substantially aligned ports, apair of spaced substantially axially aligned poppets, and meansconnecting said poppets for substantially simultaneous movement in anaxial direction but permitting slight relative lateral movement of thepoppets to obtain proper alignment of each poppet with its seat, saidconnection comprising a cable attached to each poppet and a sleevearound said cable at one extremity thereof and supported by one of saidpoppets.

7. In a valve having a pair of spaced substantially aligned ports, apair of spaced substantially axially aligned valve members, and aconnection between said members, said connection comprising a hollowtubular element secured to one of said members, a boss secured to theother of said member enterable into the bore of tubular element, and anon-resilient flexible member having its one extremity disposedinteriorly of and secured to said tubular element, said non-resilientflexible member having its opposite extremity secured to said boss, thediameters of said bore and said boss being of such respective sizes asto provide for relative lateral movement therebetween, saidnon-resilient flexible member preventing oppositely directed movementsof said valves while at the same time permitting such relative lateralmovement.

8. In a valve having a pair of spaced substantially aligned ports, apair of spaced substantially axially aligned valve members forcontrolling said ports, and a connection between said valve memberscomprising an elongated bendable element attached to each poppet and apair of telescoping slightly radially spaced sleeves through which saidelement projects, each sleeve being supported by a corresponding one ofsaid valve members, said element permitting slight relative lateralmovement of the valve members to obtain proper alignment of each valvemember with its seat while at the same time causing said valve membersto move in an axial direction substantially simultaneously.

EARL R. PRICE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 588,458 Matton Aug. 17, 1897 640,222 Price Jan. 2, 19001,848,413 Bragg Mar. 8, 1932 2,240,163 Pick Apr. 29, 1941 2,259,809Freeman Oct. 21, 1941 2,274,308 'Ischanz Feb. 24, 1942 2,345,223 UppMar. 28, 1944 2,416,091 Fitch Feb. 18, 1946 2,429,196 Price Oct. 14,1947 FOREIGN PATENTS Number Country Date 461,488 Germany of 1929

